Apparatus for removing oil from water

ABSTRACT

Improved equipment for removing oil from the surface of a body of water is disclosed. To a previously known apparatus comprised of an oleophilic fibrous batt having one or more perforated pipes embedded in it for taking away adsorbed oil, there is added a flexible shield covering the area where the pipe or pipes are located. The shield prevents water from entering into the area of the pipes and being pumped off with the oil.

United States Patent Downs [4 June 13, 1972 [54] APPARATUS FOR REMOVINGOIL 2,778,500 l/1957 Fuller ..210/D1G. 21 FROM WATER 2,788,125 4/1957Webb... ..210/242 X Inventor: Ned E'Downs, RaleishN-C- 3,556,301 l/197lSmith ..210/D1G. 21

[73] Assignee: Hercules Incorporated, Wilmington, Del. PrimaryExaminer-Samih N. Zaharna [22] Filed: Nov. 4, 1970 Attorney-Edwin H.Dafter, Jr.

[21] Appl. No.: 86,782 [57] ABSTRACT Improved equipment for removing oilfrom the surface of a [52] U.S. C1. ..2l0/242, 210/460, 210/DIG. 21 b df water i disclosed. To a previously known apparatus [51] Int. Cl ..E02b15/04 comprised f an oleophmc fib n having one or more [58] Field ofSearch ..210/23, 40, 170, 242, 460, f ted pipes dd d i i f taking awayadsorbed oil, 210/ 21 there is added a flexible shield covering the areawhere the pipe or pipes are located. The shield prevents water from en-[56] References cued tering into the area of the pipes and being pumpedoff with the UNITED STATES PATENTS Erickson ..210/242 X 3 Claims, 4Drawing Figures PATENTEDJun is I572 SHEET 1 BF 2 FIG. I

FIG. 2

NED E. DOWNS INVENTOR ATTORNEY PATENTEDJUH13 I972 3, 689 275 mu 20F 2 vNED E. DOWNS INVENTOR ATTORNEY APPARATUS FOR REMOVING OIL FROM WATERThis invention relates to a method of collecting oil from the surface ofa body of water while collecting a minimum amount of water with saidoil.

In recent years, much attention has been given to the removal of oil andoleophilic contaminants from the surface of large bodies of water suchas the oceans and coastal andinland water ways. Of the great variety oftechniques whichhave been proposed for this purpose, the most practicalare those which involve collecting the oil on some type of fibrous orfoam device from which it can easily be removed by, e.g., squeezing,pumping, or vacuum, following which the collecting member can bereturned to the water for re-use. One device, in particular, which isbelieved to be very practical is shown by Burroughs et al inco-pendingUS. application, Ser. No. 31,472. This device comprises, in essence, afibrous polyolefin body enclosing one or more perforated pipes which areattached to a pump on board an accompanying boat or barge employed todrag the fibrous body through the contaminated area. The polyolefinexhibits great affinity for oil and is thus able to absorb a substantialquantity of oil which is pumped off through the perforated pipe, orpipes, to an appropriate storage area on board the boat or barge.

The method just described derives its efficacy from the affinity of theolefin polymer, in fibrous form, for the oil. When such a fibrous bodyis thoroughly wet with oil,it is substantially completely repellent towater. Thus, in an ideal situation where the fibrous body remainscompletely wet with oil throughout the entire clean-up operation,substantially no water is collected with the oil. Such anidealcondition, however, will usually only exist in very still water. Whenthe water is turbulent, there will frequently be water washing over thefibrous body or otherwise splashing into locations from which it canflow into the perforated pipe and be pumped to storage with the oil.

It is the purpose of this invention to provide apparatus by which wateris prevented from entering into the pipes employed for pumping off theoil gathered from the surface of the water, thus insuring the collectionof substantially water-free oil even in very turbulent water. Inaccordance with this invention, it has been determined that a flexible,water impervious shell, installed over the fibrousbody in the area ofthe perforated pipe, or pipes, substantially completely eliminates waterfrom the recovered oil. The invention which accomplishes this purpose,more precisely stated, is an improvement in apparatus for removing oilfrom the surface of abody of water, said apparatus comprising anoleophilic fibrous body comprised of upper and lower surfaces andforward and aft sections and having at least one elongated perforatedpipe within the forward section adapted to remove oil therefrom and theimprovement comprising a flexible shell covering the upper and lowersurfaces of the forward section of said fibrous body substantiallycompletely while leaving at least the lower surface of the aft sectionof said fibrous body exposed and free to contact the contaminant.

The invention and the method of employing it are illustrated in theattached drawing in which:

FIG. I illustrates a preferred embodiment of the invention;

FIG. 2 illustrates the manner in which the FIG. 1 embodiment isemployed;

FIG. 3 illustrates another embodiment of the invention; and

FIG. 4 illustrates the manner in which the FIG. 3 embodiment isemployed.

With reference to FIG. 1 of the drawing the apparatus comprises afibrous polyolefin body having a forward section 2, an aft section 4, anupper surface 6, and a lower surface 8. One or a plurality of perforatedpipes 3 are embedded in the forward section of the fibrous body. Thefibrous body has the periphery of its forward section enclosed within awater-impervious flexible shell 5, adapted to enclose the area of thebody housing the perforated pipe or pipes 3. A substantial portion ofthe fibrous body, especially including the lower surface of the aftsection, is outside the shell, and in position to contact the oil on thesurface of the water.

In removing oil from the surface of a body of water using thisembodiment of the invention as shown in FlG. 2, the shellencased fibrousbody 1 rests on the water in the oil slick 7. The pump-off pipes orfittings 3 are connected topumping lines 9 which in turn are connectedto a pump or a vacuum sourceon boat 11. The fibrous body is drawnthrough the water, referring again to FIG. 1, in the direction of thearrow. The impervious flexible shell 5 completely enclosed the forwardsection of the fibrous bodyso that the nearest point at which liquid(oil and/or water) contacts the fibrous body is the point 13 which isspaced apart from the pump-off fittings in the aft section ofthe body.When the body is incontact with a layer of oil on the water surface asshown, the oleophilic fibers attract the oil and the oil is propelled bycapillary action and by the pumping force on the pump-off pipes throughthebody to the pipes and thence to the boat. As depicted, the trailingend of the apparatus rests in the water, depicting a complete removal ofthe oil from the water. In such a case, the water which contacts thetrailing edge of the body cannottravel to the forward section so long asthe remainder of the body is wet with oil.

In the normal course of operation, there willbe occasions when thefibrous body willbe in contact with water along its entire length orsubstantially along its entire length. This can happen particularly inturbulent water where waves cause the surface of the water to break, andwater momentarily displaces all of the oil in spots throughout the areabeing contacted. It can also happen in places where the oil layer isrelatively thin and all available .oil is removed quickly as, e.g.,might happen near the edge of the contaminated area. It can also happen,in rough water, that water will wash over the fibrous body and douse it.In any of these cases, water can be entrained with the oilif provisionis not made to prevent this from happening.

When using the apparatus of this invention, the point where oil is takenoff from the fibrous body is shielded from contact with water by theflexible shell 5 as shown in FIG. 1. Due to the affinity of theoleophilic fiber for the oil, the oil is absorbed and can flow bycapillary action to the pump-off fittings even though this involves areversal of the flow direction as shown by the curved directionalarrows. No such affinity exists for water and thus capillary flow of thewater is substantially non-existent. Moreover, if water does get intothe fibrous body it can be expelled therefrom and displaced by oil whileit still is well away from the pump-off point and not under theinfluence of the pumping force.

The oleophilic fiber is preferably a polyolefin such as polyethylene,polypropylene or any of the fiber-forming olefin polymers known to thetextile art for use as fibers and filaments. The most commonly used andmost preferred are those based on propylene, referred to generically aspolypropylene.

The fiber can be used in the form of a non-woven battof either staplefiber or tow which can be needle punched or sewn to afford the necessarystructural integrity. Alternatively, the batt can be prepared from aplurality of, e.g., woven or tufted layers laid up and secured togetherinto an integral structure suited for skimming the water surface. Theindividual fibers can be of any size up to about 70 denier per filament,preferably about 10 denier or less including microfibers of less than 1denier.

It is found that the volume of oil pickedup and the magnitude of thecapillary force acting on the oil are inversely related to the denier ofthe fiber, i.e., the smaller. the fiber denier, the greater theabsorption capacity. Fibers of l to 70 denier can pick up as much as1,800 percent of their own weight of oil. Fibers of less than 1 denierhave been found to pick up as much as 4,000 percent oftheir weight. Thefibers can be crimped or smooth, although crimped fibers are preferreddue to their greater structural coherence.

As shown in FIG. 3 and 4 of the drawing, the fibrous body I can beadapted to be suspended between two barges 21 on which the oil will becollected. In this case the pump-ofi means is an elongated, flexible,perforated pipe 23. A plastic pipe such as a polyethylene orpolypropylene pipe is useful for this purpose. Both of these materialshave the desirable low specific gravity, i.e., lower than that of water.Other materials of low specific gravity having the required flexibility,such as rubber, can also be used. To increase the flexibility of thepipe while improving its resistance to collapse under the influence ofthe pumping force employed to remove the oil, the pipe can have acorrugated surface configuration.

The preferred pumping force for removing absorbed oil from the fibrousbody is vacuum. This can be provided by any means known to thepractitioner. More conventional pumping means such as, e.g., centrifugalpumps, can also be employed, if more convenient.

The barrier or shell employed to shield the pump-off point of the devicecan be substantially any material which is sufficiently flexible to ridewith the surface when the water is rough and which is inert to water andto the contaminating oil, while being sturdy enough to withstand thephysical stresses encountered in rough water. The material is preferablya plastic material such as a polyethylene or polypropylene sheet. Hereagain, the low specific gravity of these materials is helpful inassuring that the overall specific gravity of the apparatus issufficiently low that it floats on the water.

The device is described above in an embodiment suitable for use on largebodies of water such as the ocean where it is drawn over the surface tocreate relative motion between the device and the oil/water interface.It can also be adapted for a stationary installation in running wateras, e.g., on a river. In this embodiment, the ends of the device aresecured on the banks of the river and the water/oil surface is permittedto pass beneath it. Oil collected from the surface is removed to storageby pumps located on the banks of the river.

in the stationary operation described above, the apparatus is helpful inareas where the pollution is intermittent but the potential forpollution exists continuously as, e.g., at the effluent stream of arefinery. Due to the omnipresent danger of pollution occurring, it isdesirable to have the apparatus permanently installed. The imperviousbarrier described hereinabove prevents the device from becomingsaturated with water during periods when no oil is present on the riversurface.

What I claim and desire to protect by Letters Patent is:

I. In apparatus for removing oil from the surface of a body of waterincluding an oleophilic fibrous web comprised of an upper and lowersurface and forward and aft sections and having at least one perforatedpipe within the forward section, said pipe being adapted to remove oilfrom said fibrous web and communicating with an oil storage facility,the improvement which comprises a water impervious flexible shellcovering the upper and lower surfaces of the forward section of the webthereby enclosing the area of the body housing the perforated pipe.

2. The apparatus of claim 1 where the flexible shell is a sheet of apolyolefin film.

3. The apparatus of claim 2 where the oleophilic fibrous web is apolyolefin.

* a: i v a

1. In apparatus for removing oil from the surface of a body of waterincluding an oleophilic fibrous web comprised of an upper and lowersurface and forward and aft sections and having at least one perforatedpipe within the forward section, said pipe being adapted to remove oilfrom said fibrous web and communicating with an oil storage facility,the improvement which comprises a water impervious flexible shellcovering the upper and lower surfaces of the forward section of the webthereby enclosing the area of the body housing the perforated pipe. 2.The apparatus of claim 1 where the flexible shell is a sheet of apolyolefin film.
 3. The apparatus of claim 2 where the oleophilicfibrous web is a polyolefin.